unning up and down from 201-212 occasionally 215 but only for a second then back down... 180deg motorad , new radiator temps show cooler on outsides left and right center top around 170-180 and bottom 150-160 range... upper radiator hoses hotter at USA driver side entrance into radiator around 186 and also right side of bled screw into engine around 15-188 but on the passenger side of bleed valve about 20deg less... turning on heater gets nice n hot normally around 140+ deg air inside vent in south florida ... nice! AHAHAHA at temperature sensor area and pipe to heater core around 200 to 205... maybe my temp sensor is bad? all temps to my knowledge with the IR hand held I have seem in range... but I see my ultra gauge showing higher than Id expect for 180 thermostat... I just replaced it with another motorad that I suspected was going bad... and I ordered this one... its white but they said the new one was 180F and I took their word for it of course... maybe I have a 190 in it? I've seen no drops when changing.. also I have new radiator, water pump, hoses ( except lower that connects to the thermostat and water pump... belt is good... expansion tank good... advise?

also adding that on highway it also reads high.. can the temperate sensor show high when in fact all is ok? there is some calcium buildup around the screw into intake where sensor mounts... no gurgling no drip outs from expansion tank for bubbling ... all seems ok... hmmm

 

You just described my problem to a T. I just ordered a new 180 thermostat I hope that takes care of it. I just did Head Gaskets and water pump last week and road tripped to LA. It would get up to 205 climbing a hill on the highway and 221 sitting in traffic. I hope that is the problem but I'm betting it is a radiator.

 

Im thinking my motorad is bad... I only had issues when I put in the "lower temp" motorad... I've read others have had issues... I'm on another thread now since I posted this one come and read... I'm going to do the inline mod but there is an OEM factory warm weather thermostat... if I stuck with the stock setup Id only go with OEM I guess now... another issue Im reading form a poster is possible lower radiator hose ( suction hose collapsing ) my heater blows HOT 140+ which I guess is normal on Max and I could watch my temps drop so that is telling me the thermostat wasn't opening or radiator issue... but I replaced radiator 8 months ago and no leaks and also water pump so Im suspecting for me its thermostat.... go with warm weather OEM is what IM reading if going stock setup

 

I would get rid of the motorad thermo... get the LR factory 180 temp thermo. then make sure you are properly bled. Also while you ar eat it do a pressure test just as a precaution to ensure that there are no loose anything that could let a little pressure out under high temps and running.

 

I'm going to do the south florida setup with thermo mod lol... Im suspecting my hoses are not collapsing since when I turn on heater it cools off.. that means there is good circulation so that seems to be just thermostat or radiator which is new... odds are on thermostat at this moment... no leaks I have noticed and I don't have to refill and no smell